Yeah, I don't exactly know how to make the custom armor I've made craftable, I'd love for some help there so that I can please some of the masses with my mods!
You need .recipe files (see the unpacked assets for hundreds of examples) for your armor pieces, and then a player.config.patch to add those new recipes to the player's default blueprints list. If you don't know how to make a .patch file, there's a very in-depth tutorial on it on these forums somewhere.
Now adding them to the workshop with the updates will be challenging. but I imagine I'll figure that out.